Each tank has an inner 9% nickel dome and an outer carbon steel dome that acts as a protective barrier to prevent leaks, accidents, or external damage. The double-dome design provides maximum safety and structural integrity, which is essential in an earthquake-active region like Taiwan. This design also adds weight and engineering complexity to the build.
In August 2025, the project team achieved a major milestone by completing the roof air raise for the first LNG tank. Because of the seismic double-dome design, the roof had a combined weight of more than 2.8 million pounds (1,307 metric tons) — the heaviest roof ever lifted by air in Bechtel’s history.
When complete, the project will have placed more than 31,500 cubic meters of concrete piles, 44,300 cubic meters of structural concrete, 6,200 metric tons of 9% nickel steel plates, 2,550 metric tons of carbon steel plates, 8,000 linear meters of piping, and 70,000 linear meters of electrical and instrumentation cables.